Technologies for joining materials that differ in composition, such as aluminum and steel, are known, including mechanical clinching, self-pierce riveting, friction stir spot welding, resistance spot welding (RSW), flow drill screws—commonly called EJOTS, friction bit joining—commonly called EJOWELD, Rivtak, resistance spot welding with process tapes—commonly called Deltaspot, GMAW fusion welding—commonly called CMT or cold metal transfer) and Resistance Element Welding (REW). Alternative methods and apparatus for joining dissimilar materials, for feeding fasteners and assessing joints, remain desirable.